coolant leak cant find source

[ccasxls]

I just got my 2001 xls not a thing wrong with it 115000 mi. 3 months later I have a coolant leak, no fluid showing externally, when driving I can sometimes faintly smell antifreeze, going through about a half gallon every 3-4 weeks, oil is not milky, not seeing vapors out of exaust after a few min from starting, I was told these engines were near bullet proof, any thoughts???? hoping its not intake gasket

 

[backfrmcolorado]

i know you have an 01 but my 94 does the same damn thing. new pump, head gaskets, every cooling/heat line, and new oversized radiator. same as you no milky oil, external leaks, or exhaust puffs. it frustrating as hell i know. im intersted in the things others will post on this problem. maybe it will help the both of us. sorry i cant help you but im in the same boat. even if it is the intake gasket wich i have been told might be my problem but unsure but it sucks it striat thru the engine a little at a time its not that hard to change.

 

[Vargas]

Which motor is in your '01?

 

[StangsandMavs]

I chased a coolant leak on my 95 for over a year... The funny thing was that it only leaked when it was bitterly cold outside.

Then spring came, and it no longer leaked...

The next winter came around and with the first cold snap, the loss of coolant returned. It turned out that there was a weakspot in the radiator that couldn't handle the change in temperature.

 

[corkey]

I also had this on my 96 Explorer , when below -20 it weeps a bit, but not enough to put the motor in danger, i just left it so far, i just say it's crying for being out when it is so cold,
it seems to leak from the rad so, i will probably be replacing it this summer

 

[Packin]

I've had a leak for several months and never could see any visible signs of the leak, until the past couple of weeks. Mine is coming from the plastic part of the radiator. I just picked up a new one this week and will be replacing it over the weekend.

 

[my98nnj]

Check the heater control valve, they tend to weep a bit. Mine does it if I shut the heat completely off, closing the valve, then open it back up again. I get the ever so slight smell of antifreeze then it goes away. Every once in a while I see a drop on the ground too. Only does it in the cold of winter.

 

[Yamaha0219]

My 1996 5.0 leaked from the heater control valve...chased that leak for months, replacing a heater core in the process (not fun)...just to have the new heater core blow a year later...smoke out the vents and antifreeze on the passenger side mat, also not fun.

 

[badge49]

It's incredibly hard to see or reach on a 4.0L SOHC, but check the area of the thermostat housing. There is a hose on top of it and one very hard to reach hose under it. It also has two temp. senders running into it and the thermostat itself. With 5 seals to leak from, I've had to take mine apart twice now in three years. If the leak is small, it may be leaking onto the block/belt and getting burned up before you see anything.

 

[StangsandMavs]

Check the heater control valve, they tend to weep a bit. Mine does it if I shut the heat completely off, closing the valve, then open it back up again. I get the ever so slight smell of antifreeze then it goes away. Every once in a while I see a drop on the ground too. Only does it in the cold of winter.

This is something to really be cautious of. On 4.0Ls, this thing sits right on top of the transmission dipstick tube.

The dipstick on my 95 started getting rusty, I had no idea why... I figured that it was just condensation. Then the fluid started turning to a rust color... I had rerouted the coolant lines to an aftermarket cooler years earlier, so I knew that this fluid was getting contaminated from something other than the radiator.

It turned out that the control valve was leaking. A quick and cheap fix. The transmission rebuild that came a few months later, that wasn't as cheap... nor as easy.

 

[ccasxls]

I have the 4.0l v6, there might be something to the coldness, because It didnt start vanishing until winter came, I'm in michigan and **** gets cold up her, thanks for the input

 

[gtyates]

I would agree on the heater control valve maybe being the culprit. Been there, done that.

 

[N1265]

I had the same problem on my '96, found out that the return hose to the coolant tank did not have a hose clamp on it by the radiator cap, replaced the "overflow line" and added a clamp and the problem was solved...

 

[jremington59]

Does anyone know the location of the heater control valve on a 5.0?